Thank you for your reply.
I tried the iso of Porteus 3.2.1 but, despite having a persistent dat file it seems Porteus does not persist packages that I install. For example, I installed Google Chrome, it is working. Now I restart Porteus, poof Chrome is gone and I need to re-install it. I checked the dat file, perfectly good.
Why is that?

I do not know what you mean by "extramod cheatcode"
I updated the Porteus.conf file that is on the USB stick (where it reads changes=...) so that it points to the dat file. Same thing I did with Porteus 3.1